Login / Signup

Total Synthesis of (+)-Trachyspic Acid 19-n-Butyl Ester.

Alex A RafanielloMark A Rizzacasa
Published in: Organic letters (2020)
The first total synthesis of the alkyl citrate trachyspic acid 19-n-butyl ester (1) is described. A formal [2 + 2]-cycloaddition of the silylketene acetal derived from lactone 6 with di-n-butylacetylene dicarboxylate 7 provided the cyclobutene diester 5 with a dr >20:1. Acid-mediated rearrangement of 5 followed by lactone ring-opening and ester protecting group manipulation eventually provided orthogonally protected aldehyde 3. A Nozaki-Hiyama-Kishi coupling between 3 and vinyl iodide 4 followed by oxidation of the resultant allylic alcohol gave enone 16, which was converted into the triester 17 (dr 6:1) by a spirocyclization/oxidative cleavage/elimination sequence. Removal of the t-butyl esters then afforded trachyspic acid 19-n-butyl ester (1).
Keyphrases
  • escherichia coli
  • nitric oxide
  • pseudomonas aeruginosa
  • ionic liquid
  • editorial comment
  • biofilm formation
  • amino acid